examples: add sram_soc example

diff --git a/.gitignore b/.gitignore
index 3fd8abfea9e887a80333e8956826d270a02b081d..09274502b8fadf43e9dcd61e74e0c42284740ed9 100644 (file)
--- a/.gitignore
+++ b/.gitignore
@@ -15,3 +15,4 @@ __pycache__/
 *.il
 *.v
 /build
+examples/build

diff --git a/examples/sram_soc.py b/examples/sram_soc.py
new file mode 100644 (file)
index 0000000..0ebe512
--- /dev/null
+++ b/examples/sram_soc.py
@@ -0,0 +1,105 @@
+import argparse
+import importlib
+
+from nmigen import *
+from nmigen_soc import wishbone
+
+from lambdasoc.cpu.minerva import MinervaCPU
+from lambdasoc.periph.intc import GenericInterruptController
+from lambdasoc.periph.serial import AsyncSerialPeripheral
+from lambdasoc.periph.sram import SRAMPeripheral
+from lambdasoc.periph.timer import TimerPeripheral
+from lambdasoc.soc.cpu import CPUSoC
+
+
+__all__ = ["SRAMSoC"]
+
+
+class SRAMSoC(CPUSoC, Elaboratable):
+    def __init__(self, *, reset_addr, clk_freq,
+                 rom_addr, rom_size,
+                 ram_addr, ram_size,
+                 uart_addr, uart_divisor, uart_pins,
+                 timer_addr, timer_width):
+        self._arbiter = wishbone.Arbiter(addr_width=30, data_width=32, granularity=8,
+                                         features={"cti", "bte"})
+        self._decoder = wishbone.Decoder(addr_width=30, data_width=32, granularity=8,
+                                         features={"cti", "bte"})
+
+        self.cpu = MinervaCPU(reset_address=reset_addr)
+        self._arbiter.add(self.cpu.ibus)
+        self._arbiter.add(self.cpu.dbus)
+
+        self.rom = SRAMPeripheral(size=rom_size, writable=False)
+        self._decoder.add(self.rom.bus, addr=rom_addr)
+
+        self.ram = SRAMPeripheral(size=ram_size)
+        self._decoder.add(self.ram.bus, addr=ram_addr)
+
+        self.uart = AsyncSerialPeripheral(divisor=uart_divisor, pins=uart_pins)
+        self._decoder.add(self.uart.bus, addr=uart_addr)
+
+        self.timer = TimerPeripheral(width=timer_width)
+        self._decoder.add(self.timer.bus, addr=timer_addr)
+
+        self.intc = GenericInterruptController(width=len(self.cpu.ip))
+        self.intc.add_irq(self.timer.irq, 0)
+        self.intc.add_irq(self.uart .irq, 1)
+
+        self.memory_map = self._decoder.bus.memory_map
+
+        self.clk_freq = clk_freq
+
+    def elaborate(self, platform):
+        m = Module()
+
+        m.submodules.arbiter = self._arbiter
+        m.submodules.cpu     = self.cpu
+
+        m.submodules.decoder = self._decoder
+        m.submodules.rom     = self.rom
+        m.submodules.ram     = self.ram
+        m.submodules.uart    = self.uart
+        m.submodules.timer   = self.timer
+        m.submodules.intc    = self.intc
+
+        m.d.comb += [
+            self._arbiter.bus.connect(self._decoder.bus),
+            self.cpu.ip.eq(self.intc.ip),
+        ]
+
+        return m
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+
+    parser.add_argument("platform", type=str,
+            help="target platform (e.g. 'nmigen_boards.arty_a7.ArtyA7Platform')")
+    parser.add_argument("--baudrate", type=int,
+            default=9600,
+            help="UART baudrate (default: 9600)")
+
+    args = parser.parse_args()
+
+    def get_platform(platform_name):
+        module_name, class_name = platform_name.rsplit(".", 1)
+        module = importlib.import_module(name=module_name)
+        platform_class = getattr(module, class_name)
+        return platform_class()
+
+    platform = get_platform(args.platform)
+
+    uart_divisor = int(platform.default_clk_frequency // args.baudrate)
+    uart_pins = platform.request("uart", 0)
+
+    soc = SRAMSoC(
+         reset_addr=0x00000000, clk_freq=int(platform.default_clk_frequency),
+           rom_addr=0x00000000, rom_size=0x4000,
+           ram_addr=0x00004000, ram_size=0x1000,
+          uart_addr=0x00005000, uart_divisor=uart_divisor, uart_pins=uart_pins,
+         timer_addr=0x00006000, timer_width=32,
+    )
+
+    soc.build(do_build=True, do_init=True)
+    platform.build(soc, do_program=True)